Abstract 18181: Real-Time Non-ECG-Gated First-Pass Perfusion MRI Enabling Concurrent Assessment of Myocardial Function and Perfusion Abnormalities

Abstract

Introduction: Combined assessment of wall motion and perfusion abnormalities from cardiac MRI (CMRI) has been shown to have a high performance for diagnosis of coronary artery disease (CAD). CMRI acquisition, however, is hindered by study length, presence of arrhythmias, and the need for synchronization with cardiac cycle via ECG gating. We developed a new non-ECG-gated CMRI technique capable of simultaneously capturing perfusion and wall motion abnormalities in a single 1-minute scan. Hypothesis: Real-time (non-ECG-gated) CMRI can detect perfusion abnormalities with high image quality and enables assessment of wall motion from the same data. Methods: A novel real-time MRI method was developed for ungated first-pass perfusion (FPP) imaging (continuous T1-weighted scan). Canines (n=5) with reversible ischemia (severe LAD stenosis) were studied using both the real-time and gated (conventional) methods. Six normal subjects and 1 patient (suspected CAD) had stress/rest real-time FFP CMRI. The patient also underwent Rb-82 stress/rest myocardial perfusion PET. Results: The real-time FPP stress/rest human studies were all of high quality. The 6 normal subjects demonstrated normal perfusion and function. In the patient, stress-induced hypoperfusion was observed, corresponding to a reversible defect on PET (Figure). In animals, real-time FPP achieved high contrast-to-noise ratio between hypoperfused/remote territories (real-time: 5.2, gated: 4.8). Wall thickening abnormalities (17 frames/s) were observed in hypoperfused areas. Conclusions: A novel approach to FPP CMRI has been developed that does not use ECG gating. Preliminary results in animals with ischemia and at stress/rest in humans were of high quality and showed expected perfusion findings. The real-time method is an attractive alternative to conventional CMRI with the advantage of simplicity (no gating), speed (concurrent MRI of function and perfusion), and potentially improved reliability.